ANS 4

Question 0

What are the general functions for the sympathetic and parasympathetic systems?

Answer 0

Sympathetic: fight or flight (stimulatory)
Parasympathetic: rest and digest (inhibitory)

Question 1

What are the two divisions of the ANS?

Answer 1

The sympathetic and the parasympathetic divisions

Question 2

What are the two sympathetic ganglia and where are they?

Answer 2

Paravertebral ganglia lie in the sympathetic trunk, beside the vertebrae.
Prevertebral ganglia are in front of the vertebral column.

Question 3

What are the 3 prevertebral ganglia and why are they named that? What synapses there?

Answer 3

Celiac ganglion
Superior mesenteric
Inferior mesenteric
They are named after the major abdominal arteries in which they are close to. Sympathetic fibers synapse there.

Question 4

Which ganglion house parasympathetic synapses? Where are these ganglion?

Answer 4

Intramural ganglion

They lie at the end of the visceral efferent pathways, close to or within the effector organ.

Question 5

Where are the sympathetic neuron cell bodies located?

Answer 5

The intermediolateral gray horn of spinal cord segmentsfrom T1-L2.

Question 6

Where are the cell bodies of the parasympathetic nervous system located?

Answer 6

In the nuclei of the brain stem and spinal cord segments S2-S4.

Question 7

What are alternative names to the sympathetic and parasympathetic nervous systems?

Answer 7

Sympathetic—>thoracolumbar

Parasympathetic—>craniosacral

Question 8

Preganglionic sympathetic fibers travel out the _______ root of the spinal cord segment and travel thru the _________ before reaching the paravertebral ganglia.

Answer 8

Ventral root

White ramus communicans

Question 9

Preganglionic parasympathetic fibers exit via the ________ nerves from the brain stem and from the _________ from the sacral region.

Answer 9

Cranial nerves

Splanchnic nerve

Question 10

Cranial nerves may never contain _________ fibers.

Answer 10

Sympathetic

Question 11

What are the 2 important functions of the sympathetic trunk?

Answer 11

1. It provides a site for the pre/postganglionic synapse for sympathetic innervation to the body wall.
2. It distributes sympathetic innervation above T1 and below L2 (where there are no sympathetic neuron cell bodies) as the entire body wall must receive sympathetic innervation.

Question 12

How do the gray and white rami communicans differ?

Answer 12

White rami: convey myelinated PREganglionic sympathetic fibers from the ventral ramus of the spinal nerve to the PARAvertebral (sympathetic) ganglion.
Gray rami: convey the UNmyelinated POSTganglionic sympathetic fibers from the ganglion back to the ventral ramus for distribution through the dorsal and ventral rami to supply the entire dermatome with sympathetic innervation.

Question 13

Which ramus is more numerous and why?

Answer 13

Gray rami
White rami are only present at vertebral levels where there is sympathetic input to the sympathetic trunk (T1-L2).
Gray rami output from the sympathetic trunk to ALL levels along the spinal column (C1 to Co4) as the entire body wall has to receive sympathetic innervation.

Question 14

What is a splanchnic nerve? What fiber does it contain and where do they go?

Answer 14

It’s a fiber that arises from the sympathetic trunk and passes medially to a PREvertebral ganglion.
It typically contains PREganglionic fibers.
These fibers are destined for viscera.

Question 15

What are the 4 parasympathetic ganglia of the head and what cranial nerves are associated with each?

Answer 15

1. Ciliary–CN III (oculomotor n)
2. Otic–CN XI (glossopharyngeal n.)
3. Pterygopalatine–CN II (facial nerve)
4. Submandibular–CN II Ciliary ganglion

Question 16

What are the 4 cranial nerves that contain parasympathetic fibers? Which one does NOT synapse in the parasympathetic ganglia of the head?

Answer 16

3,5,9,10
Oculomotor, facial, glossopharyngeal, vagus
The vagus nerve extends from the brainstem, but only synapses BELOW.

Question 17

The vagus nerve supplies Innervation to ___ of the trunk and and thorax and uses _________ ganglia exclusively.

Answer 17

2/3

Intramural

Question 18

How far distal does the vagus nerve’s innervation extend into the abdomen?

Answer 18

The vagus nerve supplies parasympathetic innervation through the abdomen as far distally as the mid transverse colon.

Question 19

What takes over for the vagus nerve in the colon?

Answer 19

From the mid transverse colon down into the pelvis, parasympathetic innervation arises from S2- S4.

Question 20

What fibers synapse or pass thru the PREvertebral ganglia?

Answer 20

Preganglionic sympathetic fibers synapse here.
Preganglionic parasympathetic fibers pass through these ganglia to synapse in the intramural ganglia of the target organ(s).

Question 21

How do fiber lengths differ between sympathetic and parasympathetic? What is the exception on the parasympathetic side?

Answer 21

sympathetic = short preganglionics and long postganglionics
parasympathetic = long preganglionics and short postganglionics.
The head and neck region exhibit an exception to the rule because the POSTganglionic fibers are relatively longer (the synapse occurs outside of the effector organ)

Question 22

ANS ganglia used for synapse include:

Answer 22

sympathetic = paravertebral and prevertebral; 
parasympathetic = intramural/terminal.